Research On Design Of Interior Permanent Magnet Synchronous Motor For Screw Pump

Screw pump compressors are widely used in many fields,such as industry and agriculture,transportation,medical treatment,national defense,scientific research,and even life,and occupy a very important position in the national economy.Scholars at home and abroad have found that PMSM has the advantages of high efficiency and good starting performance,and is suitable for use as a screw pump motor.In this paper,a permanent magnet synchronous motor(PMSM)for screw pump compressor used in air conditioning and train is studied.The motor requires a rated output power of 15 kW and a rated speed of 3000 rpm.Firstly,according to the design requirements of the motor,the main parameters such as stator inner and outer diameter,pole slot fit,stator slot shape,air gap length and rotor magnetic steel structure are selected.In order to improve the electromagnetic and mechanical properties of the motor,the rotor structure of the motor was optimized and the non-uniform air gap structure was selected to reduce the magnetic density distortion rate of the air gap.Then,the comprehensive performance of the magnetic separation bridge structure with different magnetic bridge width was compared to determine the appropriate width of the bridge.Then,the analytical calculation model of the motor is established,and the analytical algorithm of air gap magnetic density of the interior permanent magnet synchronous motor for screw pump is discussed.In this process,the influence of the saturation characteristic of magnetic circuit on the stator and rotor magnetic potential of the motor is considered.Finally,the rationality of the analytical model is verified by finite element simulation.Then,in order to reduce the vibration and noise of the motor,the radial electromagnetic force wave of the motor is analyzed according to PMSM schemes of two different pole-slot combinations,and the causes of the electromagnetic vibration of the motor are analyzed in combination with the mechanical knowledge system.Finally,referring to the finite element simulation,the analytical calculation and the experimental results,the electromagnetic vibration of two different machines is analyzed,and the optimal design scheme of the motor is determined.Finally,in order to further broaden the speed range of the motor,this paper studies a V-type magnetic steel structure motor scheme.In order to compensate the change of inductance parameters caused by magnetic circuit saturation in the process of motor load,three kinds of inductance parameter models of I-type and V-type magnetosteel structure motor are studied,and then the field-circuit coupling simulation model is established by using Simplorer module in ANSYS.The effect of different inductance parameter models on the output performance of two kinds of motor with different structures is analyzed.Two suitable flux-weakening control schemes are given.